The World Trade Center Site Memorial Competition was an open, international memorial contest, initiated by the Lower Manhattan Development Corporation (LMDC) according to the specifications of architect Daniel Libeskind, to design a World Trade Center Site Memorial (later renamed the National September 11 Memorial) on a portion of the World Trade Center site. The competition began April 28, 2003 and the winner—Michael Arad and Peter Walker's Reflecting Absence—was revealed January 14, 2004 in a press conference at Federal Hall National Memorial in New York City. The contest garnered 5,201 entries from 63 nations and 49 U.S. states, out of 13,683 registrants from all 50 U.S. states and 94 nations, making it the largest design competition in history.
On March 5, 2002, Governor George Pataki, Mayor Michael Bloomberg, and the Lower Manhattan Development Corporation (LMDC) jointly announced plans for an interim memorial to the victims September 11, 2001 and February 26, 1993 World Trade Center attacks.
On January 2, 2003, LMDC and Port Authority announced that a series of public meetings would take place to discuss a future World Trade Center Site Memorial.
The Selection Jury for the World Trade Center Site Memorial Competition were announced on April 10. The Competition began on April 28, when the Guidelines were released, Registration was opened. The LMDC accepted questions from competitors between April 28 and May 18, which were answered on its website on May 23 and removed at the end of the competition. Potential entrants were given until May 29 to register for the stated purpose of gauging the volume of entires. On May 15, the LMDC announced that it had received registrants from all 50 US states and 70 other nations; on May 30, the LMDC announced that 13,683 competitors had registered from 94 nations.